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Integrated management of anthracnose in chilli (Capsicum annuum L.)
The study entitled “Integrated management of anthracnose in chilli (Capsicum annuum L.)” was conducted at Department of Plant Pathology, College of Agriculture, Vellayani, Thiruvanathapuram during 2013-2015 with the objective to evolve an integrated management package for anthracnose in chilli. Nine...
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| Format: | Ph.D Thesis |
| Language: | English |
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Vellayani
Department of plant pathology, College of agriculture
2015
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| Subjects: |
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| 100 | |a Shilpa Treasa Chacko | ||
| 245 | |a Integrated management of anthracnose in chilli (Capsicum annuum L.) | ||
| 260 | |a Vellayani |b Department of plant pathology, College of agriculture |c 2015 | ||
| 300 | |a 188 Pages | ||
| 502 | |a MSc | ||
| 520 | 3 | |a The study entitled “Integrated management of anthracnose in chilli (Capsicum annuum L.)” was conducted at Department of Plant Pathology, College of Agriculture, Vellayani, Thiruvanathapuram during 2013-2015 with the objective to evolve an integrated management package for anthracnose in chilli. Nine isolates of the pathogen causing chilli anthracnose were isolated and based on morphological characters like colony colour, conidial shape and dimensions, the pathogens causing fruit rot disease of chilli were identified as Colletotrichum capsici (Syd.) Butler and Bisby and Colletotrichum gloeosporioides (Penz.) Penz. and Sacc. which was further confirmed and deposited at Agharkar Research Institute, Pune with accession number NFCCI- 3411 & NFCCI- 3412, respectively. Pathogenicity was proven following Koch’s postulates and virulence rating was done. From this the most virulent isolate C2, an isolate of C. capsici was selected for the further studies. The results of standard blotter test and standard agar plate method revealed that C. capsici and C.gloeosporiodes infection in chilli is seed borne in nature. The results also indicated the dominance of C. capsici (44.66 per cent) followed by C. gloeosporioides (12.00 per cent), Alternaria sp. (0.50 per cent). Saprophytic fungi recorded were Penicillium sp. (0.16 per cent) and Aspergillus sp. (0.16 per cent). The study showed that C. capsici survived for 77 days in the infected fruits and leaves in the soil and 42 days in the lab condition. The host range studies revealed that the solanaceous crops brinjal (Solanum melongena L.) and tomato (Solanum lycopersicum L.) at fruiting stage were found to be alternative hosts of C. capsici under natural conditions. However on artificial inoculation of C. capsici, brown lesions were observed on leaves of green gram (Vigna radiata L.), ivy gourd (Coccinia indica L.), sesame (Sesamum indica L.), black gram (Vigna mungo L.) and sweet potato (Ipomoea batatus L.). Natural incidence of disease was observed on weeds Richardia scabra L. (Tropical girdlepod) and Commelina benghalensis L. (Tropical spiderwort). The predominant micro-organisms isolated from chilli phyllosphere, pomoplane and rhizosphere Penicillium citrinum, Trichoderma viride, Bacillus and Pseudomonas flourescens exhibited 56.23 per cent, 64.45 per cent, 88.88 per cent and 73.33 per cent inhibition of the pathogen respectively under in vitro conditions. In vitro assay of fungicides with poisoned food technique revealed that propiconazole (0.15 per cent), difenoconazole (0.05 per cent) and mancozeb (0.2 per cent) completely inhibited the mycelial growth of C. capsici. It was followed by azoxystrobin (0.15 per cent), captan+hexaconazole (0.1 per cent), carbendazim (0.1 per cent) with mycelial inhibition of 97.77 per cent, 88.30 per cent and 83.33 per cent respectively. No mycelial growth of the pathogen was observed in chlorothalonil (0.1 per cent) amended media. Among organic preparations, panchagavya provided complete inhibition of the growth of the pathogen at all the concentrations tested. Jeevamruth provided complete inhibition only at 10 per cent concentration, whereas, the amendment of media with fish amino acid did not affect the mycelial growth of the pathogen. Chilli seedling assay of different bioagents for the control of disease on seedlings revealed that the percentage seedling mortality was lowest for the seeds treated with the biocontrol bacterium Bacillus sp. (10.46 per cent) isolated from phyllosphere and pomoplane followed by the KAU released biocontrol agent Pseudomonas flourescens (15.36 per cent). Piriformospora indica treated seeds exhibited 45.36 per cent mortality.Seedling assay with fungicides revealed that seeds treated with propiconazole (0.1 per cent) exhibited the lowest seedling mortality (10.37 per cent). A pot culture study conducted with chilli variety Vellayani Athulya to evaluate the efficacy of organic preparations, biocontrol agents and fungicides and it revealed that maximum disease suppression was provided by foliar spraying of 0.1 per cent propiconazole (62.85 per cent) and 0.05 per cent difenoconazole (61.06 per cent) at fortnightly intervals. Among the biocontrol agents, Bacillus sp. was found to be superior in suppressing the disease (59.59 per cent) and among organic preparations, panchagavya gave the maximum suppression of the disease (57.06 per cent). Based on the results of the study, an integrated management package for anthracnose in chilli is proposed as follows: Seed treatment with systemic fungicides like propiconazole (1 ml kg-1) or biocontrol agents like Pseudomonas fluorescens 10 g kg-1 prevent seed borne infection , removing infected crop debris and destroying alternative hosts such as tomato, brinjal, green gram, black gram, sesamum, ivy gourd and sweet potato and weed hosts such as Richardia scabra and Commelina benghalensis prevent disease incidence and foliar spraying of propiconazole (1 ml l-1) or difenoconazole (0.5 ml l-1) or panchagavya (2.5 ml l-1) at fortnightly intervals after the onset of the disease controls the disease. | |
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